Marine propeller



May 15, I923.

G. W. LAWSON MARINE PROPELLER Filed Oct. 1920 jfgi.

W/TIVES 8 ATTORNEYS Patented May 15, 1923. I v I i if UNITED srarssearsnrorrics.

Application filed (lctober 7, 1920. Serial No. 415,317.

7 '0 all whom it may concern: Figure 4 is'a similar view on the line 4 i50 Be it known that I, GnonsnlV. LAwsoN, of Figure 1. i a citizen of theUnited States, and a resi- Figure 5 is a similar view on the line 5-5'dent of the city of New York, borough of of Figure 1. I 5 the Bronx,county of Bronx and State of Figure 6 is a similar view on the line 66New York, have invented a new and 1mof Figure 1. proved MarinePropeller, of which the fol- Figure 7 is a similar view on the line 77lowing is a full, clear, and exact description. of Figure 1. 7

This invention relates to propellers and Beferringto the drawings bycharacters 10 more particularly to an improvement in the of reference,10 designates the hub of the construction of marine screw propellers.propeller and 11 the blades extending radi- The invention contemplatesand aims for ally therefrom. The blades are of identical one of itsprincipal objects to provide a formation and therefore a description ofone construction which will increase the power will suffice to explainthe features of con- 15 of any propeller of a given size with aministruction of all of the same. Each blade is mum expenditure ofenergy, and to this end, provided with a substantially fiat working 65.one of the main features resides in forming face 12 having the desiredpitch or angular the blades with a working face of substanrelation tothe axis of the hub. The rear tiallythe same width throughout, from theface is properly curved as at 13 to produce 2 free end of each blade tothe base, and in a stream line effect. The working faceof which the baseat its juncture with the hub, the blade is of substantially the samewidth is of a greater pitch relative to the remainder throughout thelength of the blade from its of the blade. outerfree end to its base.The forward or A further object in view is to construct a leading edge14 of the blade is in advance-of '25 propeller in which the leading edgeof the the forward end of the hub whereby the blade extends in advanceof the forward end blade will obtain an initial purchase or grip of thehub to obtain an initial purchase or on the water forward on the hub tominigrip on the water forward of the hub to mize suction at this point.Immediatelyadavoid suction. jacent the juncture of the blade with thehub, 30 A still further object of the invention is the pitch ofthe sameis increased as illusto provide a screw propeller having novel trated at15. This increased pitch curves at 30 features of construction whichmaterially a point where the proportionate distance add to theefiiciency of the same, without traveled is less than the distancetraveled materially increasing the cost of producby the remainder of theblade, whereby no v 35 tion. substantial increase in resistance isoffered i With the above mentioned and otherobat this point. The variouscross sections jects in view, some of which will more taken through theblade shown in the sevclearly appear hereafter, reference is made eralviews of the drawing, illustrate the to the following specification, theappended variations in the working surfaces of the 40 claim and theaccompanying drawings blade to show the gradual increase of the forminga part of this application, in pitch from the outer free end of theblade which; to the base at the point of its juncture with Figure 1 is afront elevation of a prothe hub. The rear or following edge 16 of pellerconstructed. in accordance with the the blade is in advance of the rearend of 45 invention. the hub inorder to reduce to a minimum Figure 2 isa side view thereof. suction at this point caused by the action ofFigure?) is a cross sectional view through the water leaving thefollowing edge 16. one of the blades taken approximately on From theforegoing it is to be understood the line 3--3 of Figure 1. that theright is reserved to embodiments to the full extent indicated by thegeneral meaning of the terms in Which the claim is expressed and byology of the same.

Having thus described my invention, I claim as new and desire to secureby Letters Patent V A propeller comprising a hub, and a series of radialblades helically arranged thereto, each of said blades having a compoundvariations in the phrasepitch the leading edge of each ofsaid bladesbeing convex and extending in advance of the forward end of the hub andthe tip of the blade, each of said blades being so formed that thegreatest convexity of the entering edge is located approximately at thegreatest Width of the. blade and the greatest pitch of the bladeinitiates at the greatest Width of the blade and increases 20 therefromto the following edge thereof.

GEORGE WI LAWSON.

